Meson-Baryon-Baryon Vertex Function and the Ward-Takahashi Identity

dc.creatorWang, Siwen
dc.creatorBanerjee, Manoj K.
dc.date1996-07-15
dc.date.accessioned2026-07-07T11:15:49Z
dc.date.available2026-07-07T11:15:49Z
dc.descriptionOhta proposed a solution for the well-known difficulty of satisfying the Ward-Takahashi identity for a photo-meson-baryon-baryon amplitude ($γ$MBB) when a dressed meson-baryon-baryon (MBB) vertex function is present. He obtained a form for the $γ$MBB amplitude which contained, in addition to the usual pole terms, longitudinal seagull terms which were determined entirely by the MBB vertex function. He arrived at his result by using a Lagrangian which yields the MBB vertex function at tree level. We show that such a Lagrangian can be neither hermitian nor charge conjugation invariant. We have been able to reproduce Ohta's result for the $γ$MBB amplitude using the Ward-Takahashi identity and no other assumption, dynamical or otherwise, and the most general form for the MBB and $γ$MBB vertices. However, contrary to Ohta's finding, we find that the seagull terms are not robust. The seagull terms extracted from the $γ$MBB vertex occur unchanged in tree graphs, such as in an exchange current amplitude. But the seagull terms which appear in a loop graph, as in the calculation of an electromagnetic form factor, are, in general, different. The whole procedure says nothing about the transverse part of the ($γ$MBB) vertex and its contributions to the amplitudes in question.
dc.descriptionA 20 pages Latex file and 16 Postscript figures in an uuencoded format. Use epsf.sty to include the figures into the Latex file
dc.identifierhttps://arxiv.org/abs/nucl-th/9607022
dc.identifierhttp://arxiv.org/abs/nucl-th/9607022
dc.identifierPhys.Rev.C54:2883-2893,1996
dc.identifierdoi:10.1103/PhysRevC.54.2883
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/192513
dc.subjectNuclear Theory
dc.titleMeson-Baryon-Baryon Vertex Function and the Ward-Takahashi Identity
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